Journal cover Journal topic
Geoscientific Instrumentation, Methods and Data Systems An interactive open-access journal of the European Geosciences Union
Geosci. Instrum. Method. Data Syst., 5, 127-142, 2016
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
19 May 2016
Mars MOURA magnetometer demonstration for high-resolution mapping on terrestrial analogues
Marina Díaz-Michelena1, Rolf Kilian2,3, Ruy Sanz1, Francisco Rios2, and Oscar Baeza2 1Payloads and Space Sciences Department, INTA, Ctra. Torrejón – Ajalvir km 4, 28850 Torrejón de Ardoz, Spain
2Geology Department, University of Trier, Behringstrasse, 54286 Trier, Germany
3University of Magellanes, Punta Arenas, Chile
Abstract. Satellite-based magnetic measurements of Mars indicate complex and very strong magnetic anomalies, which led to an intensive and long-lasting discussion about their possible origin. To make some progress in the investigation of the origin of these anomalies the MOURA vector magnetometer was developed for in situ measurements on Mars. In this work we propose the utilisation of such an instrument for future planetary on-ground surveys. The proof of its suitability is seen through testing it on various terrestrial analogues characterised by the distinct magnetic anomalies of their basement rocks: (1) a magnetite body of EL Laco (up to +110 000 nT) and its transition to surrounding andesites ( <  +2000 nT) in the northern Andes of Chile showing the highest local magnetic anomalies. The magnetite-bearing ore body has highly variable local anomalies due to its complex formation history where a significant dispersion in palaeo-orientations has been previously reported, while our vector data show relatively uniform and probably induced declinations. (2) A basaltic spatter cone of the Pali Aike volcanic field, in southern Chile, was characterised by very strong magnetic anomalies along the crater rim (up to +12 000 nT), controlled by the amount of single domain magnetites in the ground mass of the basalts. Due to their strong remanent signature, palaeo-declinations of the lavas and reorientations of collapsed blocks could be constrained by the vector data. (3) The Monturaqui meteorite crater (350 m diameter), in northern Chile, shows significant variations of its anomalies (from −2000 to  >  +6000 nT) in restricted areas of several square metres along its crater rim related to unexposed iron-bearing fragments of the impactor while its granitic and ignimbritic target rocks exhibit only very weak anomalies. (4) An area with several amphibolitic dykes, which cross-cut a Cretaceous granitoid in the southernmost Andes, where a decimetre-scale mapping was performed. In this case, pyrrhotite is the only magnetic carrier. It was formed during hydrothermal processes within the dykes. Very low (+40 to +120 nT) positive magnetic anomalies clearly depict the amount of 1–4 vol % pyrrhotite in these dykes, which is important as a mineralogical indicator as well as to detect associated gold and copper enrichment.

Citation: Díaz-Michelena, M., Kilian, R., Sanz, R., Rios, F., and Baeza, O.: Mars MOURA magnetometer demonstration for high-resolution mapping on terrestrial analogues, Geosci. Instrum. Method. Data Syst., 5, 127-142, doi:10.5194/gi-5-127-2016, 2016.
Publications Copernicus
Short summary
The present manuscript is written as the result of an exhaustive field work with MOURA instrument on relevant sites on Earth. MOURA magnetometer was developed for Mars MetNet precursor mission to Mars. In this work we have demonstrated the capabilities of the instrument in terrestrial analogues of Mars, which cover a huge variability range in the magnetic anomalies intensities. Apart from its suitability for prospections, we insist on its advanced performance regarding paleomagnetic information.
The present manuscript is written as the result of an exhaustive field work with MOURA...